[heap] report allocated object to the inline-allocation-observers

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 1aaa36baf6715bcf6f8ddab532e515f7680eca5b..5e473426028dc6dc3d21b931013781471a051836 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -2523,16 +2523,28 @@ class InlineAllocationObserver {
   intptr_t bytes_to_next_step() const { return bytes_to_next_step_; }
 
   // Pure virtual method provided by the subclasses that gets called when at
-  // least step_size bytes have been allocated.
-  virtual void Step(int bytes_allocated) = 0;
+  // least step_size bytes have been allocated. soon_object is the address just
+  // allocated (but not yet initialized.) size is the size of the object as
+  // requested (i.e. w/o the alignment fillers). Some complexities to be aware
+  // of:
+  // 1) soon_object will be nullptr in cases where we end up observing an
+  //    allocation that happens to be a filler space (e.g. page boundaries.)
+  // 2) size is the requested size at the time of allocation. Right-trimming
+  //    may change the object size dynamically.
+  // 3) soon_object may actually be the first object in an allocation-folding
+  //    group. In such a case size is the size of the group rather than the
+  //    first object.
+  virtual void Step(int bytes_allocated, Address soon_object, size_t size) = 0;
 
   // Called each time the new space does an inline allocation step. This may be
   // more frequently than the step_size we are monitoring (e.g. when there are
   // multiple observers, or when page or space boundary is encountered.)
-  void InlineAllocationStep(int bytes_allocated) {
+  void InlineAllocationStep(int bytes_allocated, Address soon_object,
+                            size_t size) {
     bytes_to_next_step_ -= bytes_allocated;
     if (bytes_to_next_step_ <= 0) {
-      Step(static_cast<int>(step_size_ - bytes_to_next_step_));
+      Step(static_cast<int>(step_size_ - bytes_to_next_step_), soon_object,
+           size);
       bytes_to_next_step_ = step_size_;
     }
   }
@@ -2863,7 +2875,8 @@ class NewSpace : public Space {
   // allocated since the last step.) new_top is the address of the bump pointer
   // where the next byte is going to be allocated from. top and new_top may be
   // different when we cross a page boundary or reset the space.
-  void InlineAllocationStep(Address top, Address new_top);
+  void InlineAllocationStep(Address top, Address new_top, Address soon_object,
+                            size_t size);
   intptr_t GetNextInlineAllocationStepSize();
   void StartNextInlineAllocationStep();